Abrégé

The present invention provides a method for producing a hollow engine valve, with which the production process can be simplified and the processing precision can be improved. To this end, the present invention provides a method for producing a hollow engine valve (1) which is provided with a valve main body (10) in which a hollow hole (10c) is formed along a valve umbrella part (10a) and a hollow shaft part (10b), wherein a solid round bar (11) forming the material of the valve main body (10) is moulded to a semi-finished article (12) by means of a single hot-forging process, the semi-finished article (12) is subjected to rotary swaging whereby the semi-finished article (12) is moulded into a semi-finished article (13), the semi-finished article (13) is subjected to necking whereby the semi-finished article (13) is moulded into the valve main body (10), and a shaft end sealing member (20) is joined to the end part of the hollow shaft part (10b) of the valve main body (10).

Classes IPC  ?

• F01L 3/14 - Refroidissement des soupapes par réfrigérant solide ou liquide, p. ex. du sodium, dans une enceinte close de la soupape
• F01L 3/20 - Forme ou structure des corps de soupape non couverts par un des sous-groupes précédents du présent groupe

Abrégé

Provided is a method for manufacturing a hollow engine valve, by which a hollow engine valve having a shaft part with a desired thickness can be relatively easily manufactured. A method for manufacturing a hollow engine valve having a hollow part formed over a range from a shaft part to an enlarged diameter section of a valve umbrella part is provided with: a rotational plastic working step for performing rotational plastic working on a hollow engine valve body semifinished product (10) which is configured from a shaft part (11) and a valve umbrella part forming portion (12) connected to the shaft part, and in which a columnar hole part (13) is formed over a range from the shaft part to an enlarged diameter section of the valve umbrella part forming portion to thereby reduce the diameter of the shaft part; a necking step for, following the rotational plastic working step, necking the hollow engine valve body semifinished product to thereby reduce the outer diameter and the inner diameter of the shaft part; and a sealing step for, following the necking step, sealing the leading end of the shaft part to obtain the hollow engine valve.

Classes IPC  ?

• F01L 3/20 - Forme ou structure des corps de soupape non couverts par un des sous-groupes précédents du présent groupe
• F01L 3/24 - Dispositifs ou accessoires de sécurité non couverts par un des sous-groupes précédents du présent groupe

Abrégé

Provided is a method for producing an engine valve (V) by subjecting a stem part (S) having a hollow part (H) to a drawing treatment using a series of dies (D1, D2, Dx, Dx+1, Dn) such that the outer diameter and inner diameter of the stem part (S) become smaller in steps and the stem part (S) is thereby molded to the desired size, whereby, after the stem part (S) has been subjected to the drawing treatment until the inner diameter of the hollow part (H) of the stem part (S) has reached a specific size (steps S11 to S15), sodium metal (Na) in the form of a solid block is introduced to the hollow part (H) of the stem part (S) (step 16-1), and a protective agent(P) made from solid paraffin or naphthalene is also introduced to the hollow part (H) of the stem part (S) such as to form a barrier between the sodium metal (Na) and the atmosphere (step S16-2), after which the stem part (S) is further subjected to a cold drawing treatment (steps S17, S18).

Classes IPC  ?

• F01L 3/14 - Refroidissement des soupapes par réfrigérant solide ou liquide, p. ex. du sodium, dans une enceinte close de la soupape
• F01L 3/24 - Dispositifs ou accessoires de sécurité non couverts par un des sous-groupes précédents du présent groupe

Abrégé

Disclosed is a hollow engine valve manufacturing method for preparing a finished hollow engine valve head from a semi-finished cup-shaped valve head that has a large diameter part at the bottom part with a closed end by reducing the diameter of the body part of the large diameter part of the semi-finished valve head, whereby it is possible to make a finished valve head by merely sealing the stem end (open end) of just a separate valve head. The diameters of the upper part and body of the large-diameter area (3a) of the partly finished valve head (3) are reduced by a rotary swaging process, a spinning process or a combination of the two; or the area is reduced by a combining a necking process as well to thereby obtain a finished valve head (30).

Classes IPC  ?

• F01L 3/20 - Forme ou structure des corps de soupape non couverts par un des sous-groupes précédents du présent groupe

Abrégé

A method for manufacturing a hollow engine valve, capable of simplifying the manufacturing process and reducing the manufacturing cost. A method for manufacturing a hollow engine valve is configured in such a manner that, in order to form the hollow shaft section of a half-finished product (1a) into a predetermined shape, the hollow shaft section is inserted in sequence into die holes (M1, M2, M (m-1), Mm, M (n-1), Mn'), which have different hole shapes, and subjected in sequence to drawing so as to reduce the outer diameter and the inner diameter of the hollow shaft section in stages and so as to stretch the length of the hollow shaft section in stages. In the method, the half-finished product (1a) is subjected to heat treatment so that the hardness thereof is lower than or equal to a predetermined level, a shaft end sealing section (15) is formed by increasing the wall thickness of the opening end of the hollow shaft section (12) toward the inside of the opening end by the die hole (Mn') of a die (Din'), the die hole (Mn') having an inner diameter adjusted to d2', and the gap in the shaft end sealing section (15) is welded.

Classes IPC  ?

• B21K 1/22 - Fabrication d'éléments de machines de parties de soupapes de soupapes-champignon, p. ex. pour moteurs à combustion interne
• B21D 41/04 - RétrécissementFermeture
• B21D 53/84 - Fabrication d'autres objets particuliers d'autres parties de moteurs, p. ex. bielles de liaison
• B21J 5/08 - Forgeage par refoulement
• F01L 3/24 - Dispositifs ou accessoires de sécurité non couverts par un des sous-groupes précédents du présent groupe

Abrégé

In the disclosed method, an engine valve (V) filled with metallic sodium (Na) within is produced by means of hardening metallic sodium (Na)—that has been liquefied through heat-melting—into rods by linearly discharging the metallic sodium (Na) in a liquid hydrocarbon (120), thus cooling the metallic sodium, then inserting these rods into a hollow section (H) through the opening (M) of a stem section (S), and then sealing the opening (M).

Classes IPC  ?

• F01L 3/14 - Refroidissement des soupapes par réfrigérant solide ou liquide, p. ex. du sodium, dans une enceinte close de la soupape

Abrégé

Disclosed is a method—for producing an engine valve (V) filled with metallic sodium (Na) within by means of: forming a stem section (S), which has a hollow section (H), at an intended size by successively drawing the stem section (S) using dies (D1, D2, Dx, Dx+1, Dn) in a manner so as to causing the size of the outer diameter and the inner diameter of the stem section (S) to contract in a stepwise fashion; and inserting metallic sodium (Na) into the hollow section (H) of the stem section (S)—wherein after drawing the stem section (S) until the inner diameter of the hollow section (H) of the stem section (S) has become a prescribed size (steps S11-S15) and then inserting the block-shaped solid metallic sodium (Na) into the hollow section (H) of the stem section (S) (step S16), the stem section (S) is further drawn (steps S17 and S18).

Classes IPC  ?

• F01L 3/14 - Refroidissement des soupapes par réfrigérant solide ou liquide, p. ex. du sodium, dans une enceinte close de la soupape

Abrégé

Provided is a method for producing a hallow engine valve which can easily produce a hallow engine valve in which strength is improved and weight is reduced. Specifically, provided is a method for producing a hallow engine valve which involves gradually reducing the size of the outer diameter and inner diameter of a hallow shaft of a semi-finished product (10a), sequentially inserting the hallow shaft into a plurality of molding holes (M1, M2', M(m-1), Mm, M(n-1), Mn) having different hole shapes so as to gradually extend the length of the hallow shaft, and forming the hallow shaft into a predetermined shape by sequentially performing said drawing process, wherein the semi-finished product (10a) is subjected to heat treatment such that the hardness thereof is equal to or less than a predetermined hardness, and the maximum thickness (t2') between the hallow shaft and an umbrella portion connected to the bottom edge of the hallow shaft is formed to be thicker than the thickness (t2) of the hallow shaft by means of molding hole (M2') of a die (Di2') which is adjusted to have a specific length (L2') and maximum inner diameter (D2').

Classes IPC  ?

• F01L 3/20 - Forme ou structure des corps de soupape non couverts par un des sous-groupes précédents du présent groupe
• F01L 3/14 - Refroidissement des soupapes par réfrigérant solide ou liquide, p. ex. du sodium, dans une enceinte close de la soupape
• F01L 3/24 - Dispositifs ou accessoires de sécurité non couverts par un des sous-groupes précédents du présent groupe

Abrégé

Conventionally, in hot forging of a valve umbrella portion of a hollow engine valve, poor finish accuracy has been provided, and in cold forging thereof, materials which can be used have been restricted. In addition, in the cold forging and the known hot forging, the number of steps for drawing is increased, which requires a large number of steps for intermediate heating processes such as annealing, with the result that the poor workability has been obtained. In view of this, a semi-finished product having a hollow and an expansion diameter portion is manufactured in advance (first step), and a press device for folding an outer cylinder (4) and an inner cylinder (5) around an entire die set (DS) is used, thereby performing drawing with a body of the semi-finished product the center in a constant temperature atmosphere at any temperature between a room temperature and 870ºC (second step).

Classes IPC  ?

• B21K 1/22 - Fabrication d'éléments de machines de parties de soupapes de soupapes-champignon, p. ex. pour moteurs à combustion interne
• B21J 5/06 - Méthodes pour forger, marteler ou presserÉquipement ou accessoires particuliers pour effectuer des opérations particulières
• B21J 5/08 - Forgeage par refoulement
• F01L 3/20 - Forme ou structure des corps de soupape non couverts par un des sous-groupes précédents du présent groupe
• F01L 3/24 - Dispositifs ou accessoires de sécurité non couverts par un des sous-groupes précédents du présent groupe

Abrégé

A method using cold forging to form an umbrella portion (1) of a hollow engine valve (V) consisting of a highly heat resistant material.  The method processes the highly heat resistant material to form a semi-finished product (11) of the umbrella portion, the semi-finished product (11) being provided with a hole (S11) having an inner diameter (φ11) which is the same as the maximum inner diameter (φ11) of a hole (S1) in the finished product, the semi-finished product (11) being also provided with an expanded diameter section (111) having a maximum outer diameter (φ12) which is the same as the maximum outer diameter (φ12) of an expanded diameter section (1a) of the finished product, and then the method obtains the finished product of the umbrella portion (1) by drawing, by multiple times of cold forging, those portions of the diameter expanded section (111) which are other than the center and lower portions of the diameter expanded section (111).

Classes IPC  ?

• F01L 3/14 - Refroidissement des soupapes par réfrigérant solide ou liquide, p. ex. du sodium, dans une enceinte close de la soupape
• F01L 3/24 - Dispositifs ou accessoires de sécurité non couverts par un des sous-groupes précédents du présent groupe